The present invention relates to an implantable prosthetic device and, more particularly, to a system and method for providing a biologically covered heart valve prosthesis.
It is well known to utilize mechanical heart valves, such as the ball check valve, and natural tissue cardiac valves to replace defective aortic and mitral valves in human patients. One type of natural tissue heart valve typically employs a porcine valve for implantation in a human, as they are very similar to human valves of appropriate size and generally are easy to procure.
Prior art teaches the concept of removing an aortic heart valve from a pig, treating it with an appropriate fixation solution, which may include a glutaraldehyde solution, and mounting the valve into a stent.
A stent typically is formed of a resilient material, such as a plastic (e.g., DELRIN). Examples of various stent structures are disclosed in U.S. Pat. No. 3,983,581, U.S. Pat. No. 4,035,849. The stent usually is covered with a fabric material, such as DACRON or a suitable textile material. The fabric material provides structure for securing the valve relative to the stent. The stented heart valve prosthesis may be implanted into a patient for a heart valve replacement.
The present invention relates to a system and method for covering a stented heart valve prosthesis with biological tissue, such as pericardium. The prosthesis includes a stent having a generally annular inflow end spaced from an outflow end. The stent is covered with a fabric material. A heart valve is mounted within the stent, such as by sutures securing the heart valve to the fabric covering. One or more sheets of the biological tissue is applied to the stented prosthesis so as to cover all exposed areas of the fabric material. As a result, there is a reduced likelihood of clot formation and a decreased likelihood that infection will occur after the prosthesis is implanted.
One aspect of the present invention provides a heart valve prosthesis that includes a stent having an annular base portion and a plurality of stent posts extending therefrom. The stent has a fabric covering. A natural tissue heart valve is mounted within said stent. At least one sheet of biological tissue covers all exposed fabric covering.
Another aspect of the present invention relates to a system for covering a fabric-covered stent with biological tissue. The stent has a plurality of stent posts extending in a first direction from an annular base portion of the stent. The stent has a fabric implantation flange extending radially from an exterior portion of the base portion, with the implantation flange having an inflow side and an outflow side. The system includes a pair of annular sheets of biological tissue dimensioned and configured for covering the inflow and outflow sides of the implantation flange in a sandwich-like manner. At least one additional sheet of pericardium covers a radially outer portion of each of the fabric-covered stent posts, whereby the fabric-covered exterior portions of the stent are completely covered with biological tissue.
Still another aspect of the present invention relates to a method for covering a heart valve prosthesis with biological tissue, the heart valve prosthesis including a stent having an annular base portion and a plurality of stent posts extending therefrom. A fabric material covers at least a radially exterior portion of the stent and a natural tissue heart valve is mounted within the fabric-covered stent. The method includes the step of covering all exposed fabric material with animal pericardium.